1. Field of the Invention
The present invention relates generally to the field of automatic controls. More specifically, the present invention is directed to a device and method for controlling the interior temperature in the passenger compartment of a motor vehicle.
2. Description of the Related Art
In operating units for controlling air conditioners in motor vehicles, NTC or PTC elements are used to measure the interior temperature of the motor vehicle. In this case, a small, quietly running fan is used to suck in the inside air from the passenger compartment and to ventilate the interior temperature sensor with the sucked-in air. This fan motor runs as soon as, for example, an opening signal of the central locking system, the interior light or the auxiliary heating is activated and this is detected by the air conditioner control unit. That is to say, the fan in the motor is already running before the ignition is switched on, or still runs on a while after the ignition has been switched off in order to cool the interior temperature sensor. The noise disturbance occurring in this case from the fan motor is felt to be troublesome by the vehicle user.
U.S. Pat. No. 5,333,784 discloses a radiation sensor for use in air conditioners of a motor vehicle. In the case of this device, the electric signal corresponding to the temperature of the measured object and emitted by the radiation sensor is fed to a microprocessor which sets the desired temperature of a device. This is performed by driving a heating system or a fan.
It is an object of the present invention to specify a device and method for controlling the interior temperature in the passenger compartment of a motor vehicle, in which the noise disturbance from the fan motor is eliminated and reliable control of the interior temperature control is ensured nonetheless. Other objects and advantages of the present invention will be apparent from the following summary and detailed description of the preferred embodiments.